Industrial processes generate an enormous amount of thermal energy. According to at least one survey, the amount of heat generated in the chemical industry, petroleum refineries, and forest product industries within the United States of America is on the order of approximately 6,000 trillion Btu's. That number does not include heat generated in other processes and industries, such as boiler, food, energy, metal and metallurgy, heating ventilation and air conditioning (HVAC) and many other industries. 6,000 trillion Btu's is equivalent to approximately 5 billion U.S. dollars. Out of the 6,000 trillion Btu's, it is believed that only 52% are utilized, and the remaining energy is wasted, or otherwise lost to the environment.
Large-scale thermoelectric generators are known. For example, U.S. Pat. No. 4,734,139 provides a thermoelectric generator module which is formed with a hot side heat exchanger in contact with a series of individual thermoelectric semiconductor modules. The semiconductor modules are arranged such that heat flows through the modules. Each semiconductor module is electrically coupled so that their output may be combined to produce a large quantity of electrical power.
Thermoelectric materials, in accordance with known physical concepts, generate an electrical current flow in response to a thermal gradient across the thermoelectric generator.
In industrial environments, hot processes are generally insulated in order to inhibit, or otherwise minimize, unwanted heat flowing from the hot process. This thermal insulation increases the efficiency of the process, while simultaneously facilitating safety of the installation itself. The insulation may be made of several layers of thermal insulators. The thickness of the insulation can vary often between a couple of inches to tens of inches, depending upon the requirements.
While it would be useful to utilize thermoelectrical generators to convert all otherwise wasted industrial thermal energy to electricity, the real-world needs for thermal insulation generally inhibit heat flow to such an extent that simple application of thermoelectrical generation principles to processes is cost prohibitive. Moreover, providing a thermal insulator in the heat flow path of a thermoelectric generator reduces the thermal gradient across the thermoelectric generator, and accordingly reduces generation efficiency.
Providing an industrial, large-scale, thermoelectric generator that is able to provide large quantities of electricity, while simultaneously providing thermally insulative properties to a process would represent an important step in both increasing process efficiencies, while reclaiming otherwise lost energy.